Make several diagonal slashes across each chicken breast. Tip the other ingredients into a wide shallow bowl and swirl them together until everything is well mixed. Add the chicken breasts and turn them in the mixture until they are evenly coated. At this point you can cover the dish with cling film and chill the chicken for 24 hours, but it’s also fine to cook them straight away.
Preheat the grill or light the BBQ. Then cook the chicken for 5-6 minutes each side, turning once and brushing or spooning over more marinade as you go, until the chicken is browned and glossy. Serve the chicken on a bed of dressed salad leaves.